This invention relates to an adapter plug for a rechargeable electric appliance for personal use, such as a dry shaving apparatus, equipped with flat contact pins, having a plug case with contact pins for connecting to a socket-outlet and a case wall provided with accommodating holes suitable for flat contact pins in order to close a circuit.
Various countries are known to have different, largely standardized plug systems. The actual plugs differ fundamentally first in the shape of their contact pins, which are round or flat, for example, and then in the distance between the contact pins. Appliance plugs with relatively close set contact pins of a blade-shaped configuration, also called flat contact pins, are known to be intended for a voltage range from 90 to 125 volts. Because of the small distance which may separate flat contact pins, it is customary in various countries where a plug system of this type is installed nation-wide in all households for these flat contact pins to also be fitted in electric appliances equipped with rechargeable storage cells in such a way as to be pushed and swiveled out of the appliance case, with the relative distances of the flat contact pins to the outer walls of the plug case or to the outer walls of the electric appliance being smaller than the compulsory plug contours and hence clearances and creepage distances from the user""s hand laid down in some countries.
An electric appliance of the type initially referred to is known from German utility model G 83 29 691 (U1), for example. The appliance plug of the rechargeable shaving apparatus is slidably arranged at one end of the shaver housing. The two blade-shaped contact pins fastened to a plug case are pushed out of one of the two narrow sides of the shaver housing by means of an actuator switch arranged in the bottom of the housing in order to be connected to a socket-outlet of an electrical power supply. The socket-outlet, for example, may be a fixed arrangement in a room wall of a house or be part of an adapter plug.
Rechargeable electric appliances such as shavers of the type referred to in the foregoing are known to be equipped with charging circuits for rechargeable storage cells whose voltage range is conventionally 90 to 270 volts. It is thus possible for electric appliances of this type equipped with flat contact pins to be recharged also in those countries with a plug system based on contact pins of a different shape and arrangement. In order to be able to recharge an electric appliance equipped with flat contact pins, adapter plugs are available which have a shell-shaped case wall, two end walls, round contact pins projecting from one of the end walls, and accommodating holes suitable for flat contact pins that are provided in the end wall facing away from the end wall carrying the round contact pins and through which the flat contact pins of an electric appliance make contact with live parts of the projecting contact pins. An adapter plug of this type equipped with round contact pins, for example, is illustrated in FIG. 1. For safety reasons some countries approve a plug of this type only when the relative distance of the contact pins and the accommodating holes to the outer wall of the plug case is equal to or greater than the required and hence compulsory clearance and creepage distance to the user""s hand. In countries with voltages of over 200 V this safety clearance amounts to 8 mm, for example.
From DE 84 01 378 U1 there is known an adapter plug equipped with round contact pins, whose end wall remote from the contact pins is provided with a circumferential safety wall. With this adapter plug it is only possible to connect an electric appliance with the help of a power cable equipped with flat contact pins; the direct connection of a rechargeable electric appliance equipped with flat contact pins is, however, not possible.
It is an object of the present invention to provide an adapter plug of the type initially referred to, which ensures the connection of a rechargeable electric appliance equipped with flat contact pins to a circuit while allowing for a sufficient safety clearance.
According to the present invention this object is accomplished with an adapter plug of the type initially referred to by providing the safety wall with at least one recess for the accommodation and connection of electric appliances equipped with flat contact pins.
An essential advantage of the invention is that it provides an adapter plug meeting the safety regulations simply by re-designing and rearranging a safety wall that already exists. Furthermore, as the embodiments shown in FIGS. 3 and 4 show, it is possible to manufacture the adapter plug according to the invention at lower cost as the result of saving material.
In an embodiment of the present invention, the safety wall is cylindrically shaped and provided with a U-shaped recess for connecting the adapter plug to the flat contact pins of the electric appliance.
According to a further embodiment of the present invention, the safety wall sections are arranged parallel to each other on the case wall.
According to yet another embodiment which is adapted preferably to a specific rechargeable electric appliance such as a shaving apparatus having push-out flat contact pins, provision is made for the distance between opposite safety walls to be equal to the distance between two opposite walls of the electric appliance to be accommodated or to the thickness of the appliance.
According to a preferred embodiment of the invention, the distance between opposite safety wall sections may be selected slightly larger than the distance between two opposite walls of an electric appliance to be accommodated or the thickness of the appliance while still allowing for the compulsory safety clearance.